Offshore terminals for mooring a tanker for transferring fluid between the ship and an underwater pipeline, are available in a wide variety of configurations. However, where a supercooled liquified gas such as LNG (liquified natural gas) must be transferred, a large number of such systems are not usable. Ice tends to form around any pipes that carry LNG, even those above water, and otherwise flexible hoses tend to become hardened because of the extremely low temperature. The use of long hoses that lie in the water for pick up by ships is impractical. Underwater swivel units are usually impractical, because LNG molecules are small and therefore readily leak, and underwater swivel units tend to freeze into an unmovable condition unless costly precautions are taken. While loading arms and hoses are available for carrying LNG, they are normally useable in only moderate to short lengths, because they become unweildy when very long.
Despite the difficulties involved in transferring LNG through offshore terminals, such terminals have considerable advantages over fixed docks. An important advantage is that offshore terminals can be placed far enough from the shore to avoid dangers to homes and other property near the shore in the event of an accident. In addition, an offshore terminal can avoid the expense of a complete port facility in remote areas, and can enable the transference of LNG even in rough weather. An offshore terminal of relatively modest cost would therefore be of considerable advantage in the transport of supercooled liquids such as LNG.